This invention relates to an electron beam exposing method and electron beam exposing apparatus.
Electron beam exposing apparatus is adapted to project electron beam on a predetermined area of a photoresist layer on a semiconductor wafer or an IC or LSI pattern mask to describe a desired pattern on the photoresist layer. It is required that the electron beam exposing apparatus can accurately describe a desired pattern with high precision. In such apparatus it is said that the faster the describing speed the better. In order to enhance the pattern accuracy, the width of electron beams projected onto the photoresist is made relatively small, for example, of the order of about 0.5 .mu.m. It is true that if the width of the beam diameter is made smaller a pattern can be sufficiently accurately described, but it takes a longer time to describe a predetermined pattern, since the smaller beam diameter and thus the smaller unit exposure area (i.e., the limit exposure area when the electron beam is projected on the photoresist layer without being deflected) are involved. Thus, there is a problem in the prior art that a describing speed is slow. A pattern to be described usually includes not only a circuit pattern to be exactly described, but also a mark pattern such as a manufacture number, manufacture date and pattern data which is sufficient, if legible, and which is not required to be enough accurate. In this case, an unnecessarily longer describing time or exposure time is required, because even the mark pattern must be described by an electron beam of smaller diameter.